login
This site is supported by donations to The OEIS Foundation.

 

Logo

110 people attended OEIS-50 (videos, suggestions); annual fundraising drive to start soon (donate); editors, please edit! (stack is over 300), your editing is more valuable than any donation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A120934 Least prime p such that the interval [p,p+log(p)] contains n primes. 2
2, 11, 457, 3251, 165701, 10526557, 495233351, 196039655873, 10687033762033, 79006533276941, 4313367040646743, 1740318019946551931 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Soundararajan states that, on average, there is one prime in the interval [k,k+log(k)] for any number k. Is there an upper limit to the number of primes in such an interval? Not if the prime k-tuple conjecture is true, in which case a(n) exists for all n. Note that a(n) > e^A008407(n). See A120935 for the largest prime in the interval.

a(n) begins a sequence of n primes whose prime pattern is one of the patterns in the n-th row of A186634. For example, the sequence of four consecutive primes beginning with 3251 is (3251, 3253, 3257, 3259), which has pattern (0, 2, 6, 8), which is in the 4-th row of A186634.

LINKS

Table of n, a(n) for n=1..12.

K. Soundararajan, The distribution of prime numbers

Eric Weisstein's World of Mathematics, Prime k-Tuple Conjecture

FORMULA

This sequence grows superexponentially; a weak lower bound is a(n) >> (log n)^n. It seems that a(n) > n^n. - Charles R Greathouse IV, Apr 18 2012

EXAMPLE

a(2)=11 because p=11 is the first prime with log(p)>2 and 11+2 is prime.

MATHEMATICA

i=1; Table[While[p=Prime[i]; PrimePi[p+Log[p]]-PrimePi[p]+1< n, i++ ]; p, {n, 5}]

CROSSREFS

Cf. A120936 (number of primes in the interval [n, n+log(n)]), A020497.

Sequence in context: A012950 A012979 A013109 * A000886 A128855 A206846

Adjacent sequences:  A120931 A120932 A120933 * A120935 A120936 A120937

KEYWORD

hard,nonn,nice

AUTHOR

T. D. Noe, Jul 21 2006

EXTENSIONS

a(12) from Donovan Johnson, Apr 18 2012

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified October 30 07:54 EDT 2014. Contains 248796 sequences.